Greene, a close pal of Warburton, said he found the 800m runner’s demise “hard to process”, and stuck up for Williams too, even though the son of former Wales and Lions rugby internional JJ Williams has never been a close ally.

“Gareth sent me a text to tell me the news and I was almost physically sick,” revealed Greene.

“I don’t know anyone who has failed a test before personally until that moment.

“I found it hard to process because he is one of my best friends.

“We used to live together for a couple of years and trained together.

“To read that about him was shocking because I know he is not that sort of person and my heart sunk for him.

“I have since spoken with Gareth and he’s disappointed about everything but focused on his task of getting to the bottom of things.

“Hopefully he can find exactly how it’s happened and can move on from there. “

Greene was unequivocal in his backing of Williams, insisting he is not the type of person to seek an unfair advantage through any means.

“Rhys and I aren’t the best of pals and we are quite fierce rivals,” admitted Greene.

“But I know he is not the sort of guy who would take things to get an advantage.

“I sympathise with his situation. Hopefully they can both sort things out and wear a Welsh vest again.

“I’m not sure what they are going through because I have not been in their situation but I can’t imagine it’s pleasant.”

Warburton and Williams now face a battle to clear their names ahead of hearings later this year as they investigate what supplements they have taken.

Dai Greene (Image: PA Wire)

“Having spoken to Gareth, I know about the ins and outs about how it maybe has come about but I don’t want to comment on that because it is an ongoing process,” added Greene.

“It has not been proven where it has come from yet and until that is we don’t know what goes on.

“The golden rule is you are responsible for what you take but we will have to see what happens.”

Greene urged the Welsh Athletics team in Glasgow to rise above the turmoil.

“It’s disappointing because they are two of our top guys,” said Greene.

“It would have a bit of a negative morale but the last thing those two guys would want is to have everyone affected by it.

“They have wished us all the best and have been supportive.

“It’s sad this has happened just as we go into a major competition because this is our chance to showcase Welsh athletics.

“But there are plenty of talented people here and the attention should switch to them.”

Team Wales have managed to overcome the doping controversy, absence of injured world champions and Olympic silver medallist Fred Evans having his accreditation refused.

Despite these turbulent preparations, Wales have compiled a medal tally of 22 surpassing the 19-haul in Delhi of four years ago less than halfway through the Games and on their way to the Glasgow target of 27.

“The more household names who can’t be here is disappointing but those who are have done incredibly well,” added Greene.

“We seem to be punching above our weight with our medal tally. Fingers crossed that will continue this week.”